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wireshark/epan/dissectors/packet-macsec.c

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/* packet-macsec.c
* Routines for MACsec dissection
* Copyright 2013, Allan W. Nielsen <anielsen@vitesse.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/etypes.h>
void proto_register_macsec(void);
void proto_reg_handoff_macsec(void);
#define TCI_V_MASK 0x80
#define TCI_ES_MASK 0x40
#define TCI_SC_MASK 0x20
#define TCI_SCB_MASK 0x10
#define TCI_E_MASK 0x08
#define TCI_C_MASK 0x04
#define TCI_AN_MASK 0x03
static int proto_macsec = -1;
static int hf_macsec_TCI = -1;
static int hf_macsec_TCI_V = -1;
static int hf_macsec_TCI_ES = -1;
static int hf_macsec_TCI_SC = -1;
static int hf_macsec_TCI_SCB = -1;
static int hf_macsec_TCI_E = -1;
static int hf_macsec_TCI_C = -1;
static int hf_macsec_AN = -1;
static int hf_macsec_SL = -1;
static int hf_macsec_PN = -1;
static int hf_macsec_SCI_System_identifier = -1;
static int hf_macsec_SCI_port_number = -1;
static int hf_macsec_ICV = -1;
/* Initialize the subtree pointers */
static gint ett_macsec = -1;
static gint ett_macsec_tci = -1;
/* Code to actually dissect the packets */
static int dissect_macsec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
unsigned sectag_length, data_length, icv_length = 16;
unsigned sectag_offset = 0, data_offset, icv_offset;
guint8 tci_an_field;
proto_item *macsec_item, *tci_item;
proto_tree *macsec_tree, *tci_tree;
tvbuff_t *next_tvb;
tci_an_field = tvb_get_guint8(tvb, 0);
if ((tci_an_field & TCI_V_MASK) != 0) { /* version must be zero */
return 0;
}
if (tci_an_field & TCI_SC_MASK) {
sectag_length = 14;
} else {
sectag_length = 6;
}
/* Check for short length */
if (tvb_captured_length(tvb) <= (sectag_length + icv_length)) {
return 0;
}
data_offset = sectag_length;
data_length = tvb_captured_length(tvb) - sectag_length - icv_length;
icv_offset = data_length + data_offset;
next_tvb = tvb_new_subset_length(tvb, data_offset, data_length);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MACSEC");
col_set_str(pinfo->cinfo, COL_INFO, "MACsec frame");
if (tree) {
macsec_item = proto_tree_add_item(tree,
proto_macsec, tvb, 0, sectag_length, ENC_NA);
macsec_tree = proto_item_add_subtree(macsec_item, ett_macsec);
tci_item = proto_tree_add_uint_format(macsec_tree, hf_macsec_TCI, tvb,
sectag_offset, 1, tci_an_field,
"TCI=0x%02x: V=%d, ES=%d, SC=%d, SCB=%d, E=%d, C=%d, AN=%d",
tci_an_field,
((TCI_V_MASK & tci_an_field) ? 1:0),
((TCI_ES_MASK & tci_an_field) ? 1:0),
((TCI_SC_MASK & tci_an_field) ? 1:0),
((TCI_SCB_MASK & tci_an_field) ? 1:0),
((TCI_E_MASK & tci_an_field) ? 1:0),
((TCI_C_MASK & tci_an_field) ? 1:0),
(TCI_AN_MASK & tci_an_field));
tci_tree = proto_item_add_subtree(tci_item, ett_macsec_tci);
proto_tree_add_item(tci_tree, hf_macsec_TCI_V, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_TCI_ES, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_TCI_SC, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_TCI_SCB, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_TCI_E, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_TCI_C, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tci_tree, hf_macsec_AN, tvb, sectag_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(macsec_tree, hf_macsec_SL, tvb, sectag_offset + 1, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(macsec_tree, hf_macsec_PN, tvb, sectag_offset + 2, 4, ENC_BIG_ENDIAN);
if (sectag_length == 14) {
proto_tree_add_item(macsec_tree, hf_macsec_SCI_System_identifier,
tvb, sectag_offset + 6, 6, ENC_NA);
proto_tree_add_item(macsec_tree, hf_macsec_SCI_port_number, tvb,
sectag_offset + 12, 2, ENC_BIG_ENDIAN);
}
call_data_dissector(next_tvb, pinfo, tree);
proto_tree_add_item(macsec_tree, hf_macsec_ICV, tvb, icv_offset,
icv_length, ENC_NA);
}
return tvb_captured_length(tvb);
}
void
proto_register_macsec(void)
{
static hf_register_info hf[] = {
{ &hf_macsec_TCI, { "TAG Control Information", "macsec.TCI",FT_UINT8,
BASE_HEX, NULL, 0xfc, NULL, HFILL} },
{ &hf_macsec_TCI_V, { "VER", "macsec.TCI.V", FT_UINT8, BASE_HEX,
NULL, 0x80, NULL, HFILL} },
{ &hf_macsec_TCI_ES, { "ES", "macsec.TCI.ES", FT_UINT8, BASE_HEX, NULL,
0x40, NULL, HFILL} },
{ &hf_macsec_TCI_SC, { "SC", "macsec.TCI.SC", FT_UINT8, BASE_HEX, NULL,
0x20, NULL, HFILL} },
{ &hf_macsec_TCI_SCB, { "SCB", "macsec.TCI.SCB", FT_UINT8, BASE_HEX,
NULL, 0x10, NULL, HFILL} },
{ &hf_macsec_TCI_E, { "E", "macsec.TCI.E", FT_UINT8, BASE_HEX, NULL,
0x08, NULL, HFILL} },
{ &hf_macsec_TCI_C, { "C", "macsec.TCI.C", FT_UINT8, BASE_HEX, NULL,
0x04, NULL, HFILL} },
{ &hf_macsec_AN, { "AN", "macsec.AN", FT_UINT8,
BASE_HEX, NULL, 0x03, NULL, HFILL} },
{ &hf_macsec_SL, { "Short length", "macsec.SL", FT_UINT8, BASE_DEC,
NULL, 0xFF, NULL, HFILL} },
{ &hf_macsec_PN, { "Packet number", "macsec.PN", FT_UINT32, BASE_DEC,
NULL, 0xFFFFFFFF, NULL, HFILL} },
{ &hf_macsec_SCI_System_identifier,
{ "System Identifier", "macsec.SCI.SytemIdentifier",
FT_ETHER, BASE_NONE, NULL, 0x00, NULL, HFILL} },
{ &hf_macsec_SCI_port_number,
{ "Port number", "macsec.SCI.port_number",
FT_UINT16, BASE_DEC, NULL, 0xFFFF, NULL, HFILL} },
{ &hf_macsec_ICV, { "ICV", "macsec.ICV",
FT_BYTES, BASE_NONE, NULL, 0x00, NULL, HFILL} }
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_macsec,
&ett_macsec_tci
};
/* Register the protocol name and description */
proto_macsec = proto_register_protocol("802.1AE Secure tag", "MACsec", "macsec");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_macsec, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_macsec(void)
{
dissector_handle_t macsec_handle;
macsec_handle = create_dissector_handle(dissect_macsec, proto_macsec);
dissector_add_uint("ethertype", ETHERTYPE_MACSEC, macsec_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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